1. Field of the Invention
The invention relates to a standard converting apparatus and, more particularly, to an apparatus for converting a television signal according to one standard, such as, the high definition television standard in which each field has a large number of lines into a television signal according to another standard, such as the NTSC standard in which each field has fewer lines.
2. Description of the Prior Art
A high definition television (referred to hereunder simply as "HD") standard having 1125 lines and capable of the reproduction of a high resolution picture has been proposed.
It has been desired to add the functions of reproducing a still picture of a desired scene and of slow reproduction to a standard converting apparatus for converting a television signal of the HD standard into that of the NTSC standard, and thereby make possible reproduction of a still picture as well as slow reproduction using a monitor of the NTSC standard with respect to a television signal sent in the HD standard.
In order to perform the reproduction of a still picture and slow reproduction, it has been proposed that data of one frame of a television signal be stored in a frame memory to permit the identical data to be read consecutively and at slower speed. However, since one frame of the television signal is made up of an odd field and an even field, double images are reproduced in a moving picture when a still picture is reproduced from one stored frame of data.
Therefore, in order to execute the reproduction of a still picture and slow reproduction in accordance with the prior art, one field of a television signal is stored in a field memory, and a picture of one frame is developed using data of the one field, and the identical data are read out consecutively.
If one frame picture is developed using one field data as mentioned above, there is a problem that a distinct picture cannot be obtained because only the data of one field are employed.